The invention relates to semiconductor technology, and more specifically to embedded memories.
Capacitors are elements that are used extensively in semiconductor devices for storing an electrical charge. Capacitors essentially comprise two conductive plates separated by a dielectric material. The capacitance, or amount of charge held by the capacitor per applied voltage, depends on a number of parameters such as the area of the plates, the distance between the plates, and the dielectric constant value for the dielectric material between the plates, for example. Capacitors are used in filters, analog-to-digital converters, memory devices, control applications, and many other types of semiconductor devices.
One type of capacitor is an MIM capacitor, which is frequently used in mixed signal devices and logic devices, such as embedded memories. MIM capacitors are used to store a charge in a variety of semiconductor devices. MIM capacitors are often used as a storage node in a memory device, for example. An MIM capacitor is typically formed horizontally on a semiconductor wafer, with two metal plates sandwiching a dielectric layer parallel to the wafer surface. Often, one of the metal plates is formed in a metallization layer or metal interconnect layer of a semiconductor device.
Conventionally, formation of an MIM capacitor requires three or more mask layers and complex processing, affecting throughput and process cost. This complex processing potentially induces more yield loss. Thus, embedded memories requiring less mask layers are desired.